热轧高强船板拉力分层原因分析及措施

Analysis and Study on the Tensile Test Separation of Hot Rolled High Strength Hull Plate

为了降低热轧高强船板钢的拉力分层比率,对判定合格与不合格的拉伸残样进行了金相、扫描等对比检验,并且收集了所有试样对应钢板的生产工艺和技术参数,采用回归等统计分析方法得出造成拉力分层的根本原因是锰含量中心偏析,直接原因是裂纹与孔洞;利用回归方程预测,锰含量降低到1.30%以下时可以显著降低分层率。采取措施后拉力分层率由8.07%降低到1.25%,且可以稳定控制在2.0%以下。

In order to reduce the tensile test separation ratio,comparisons and inspection have been done between qualified and unqualified tensile test samples of hot rolled high strength hull plate with metallographic and SEM,and processing and technical parameters of each plate were gathered.With regression analysis and other statistical methods,we can know the direct reason causing the separation in tensile test sample is crack and hole which is caused by central manganese segregation.With regression analysis,we can know reducing the manganese content to 1.30% is an effective measure.The separation ratio can be reduced from 8.07% to 1.25%,and it also can be controlled steadily below 2.0% due to the lower manganese content.